1. Field of the Invention
The present invention relates to a direct liquid type writing instrument provided with an ink reservoir containing ink.
2. Description of the Related Art
A conventional direct liquid type writing instrument of this type includes an ink reservoir containing ink, a junction core extending on a center axis in front of the ink reservoir, and a pen body provided on a tip end side of the junction core.
A problem with the conventional direct liquid type writing instrument constructed as described above is that when the instrument is used in an environment in which air pressure changes, for example, an internal pressure is higher than an external pressure as within an aircraft, ink contained in the ink reservoir runs over from a pen tip, whereby a paper surface is stained.
The present invention has been achieved to solve the above problem, and accordingly an object thereof is to provide a direct liquid type writing instrument which can be used as usual without running-over of ink even in an environment in which the internal pressure is higher than the external pressure.
To attain the above object, a direct liquid type writing instrument according to the present invention comprises, an ink reservoir including a main ink reservoir containing ink, a pen core chamber, and a sub ink reservoir which is provided between said main ink reservoir and said pen core chamber and communicates with said main ink reservoir via a small hole; a junction core disposed in said pen core chamber and extending on a center axis; a pen body provided integrally with a tip end side of said junction core or separately so as to be in contact with the tip end of said junction core; an opening/closing valve provided between said sub ink reservoir and said pen core chamber to normally isolate said pen core chamber from said sub ink reservoir and to be operated so that said pen core chamber communicates with said sub ink reservoir when said pen body is operated; an ink absorption body capable of absorbing ink, provided in said pen core chamber; and an ink suction body provided in said sub ink reservoir for moving into said small hole in association with an operation of said opening/closing valve.
When the writing instrument is first used, the pen body is operated to open the opening/closing valve, by which the pen core chamber is caused to communicate with the sub ink reservoir. At the same time, the ink suction body is moved into the small hole located between the main ink reservoir and the sub ink reservoir in association with the operation of the opening/closing valve. Thereby, the ink in the main ink reservoir is sucked into the sub ink reservoir and is further supplied into the pen core chamber communicating with the sub ink reservoir so that the ink is absorbed by the junction core and the ink absorption body in the pen core chamber. Thus, ink spreads over the pen body, by which writing can be made possible.
When writing is performed, since the operation of the pen body is released, the opening/closing valve isolates the pen core chamber from the sub ink reservoir, and also the ink suction body returns into the sub ink reservoir. Writing can be continued without the operation of the pen body until the ink absorbed by the ink absorption body is consumed. When the writing line becomes faint, the pen body is operated again, by which ink is sucked from the main ink reservoir as before, being supplied into the pen core chamber, and is absorbed by the junction core and the ink absorption body in the pen core chamber.
Even when the writing instrument is used in an environment in which the internal pressure is higher than the external pressure, since the pen core chamber is isolated from the sub ink reservoir and the main ink reservoir by the opening/closing valve, the ink sent from the sub ink reservoir and the main ink reservoir does not run over to the outside, and writing can be performed with the pen body using the ink absorbed by the ink absorption body in the pen core chamber. When the writing line becomes faint, the pen body is operated to open the opening/closing valve to supply the ink sucked from the main ink reservoir from the sub ink reservoir to the pern core chamber. At this time, even if the opening/closing valve causes the pen core chamber to communicate with the sub ink reservoir, the ink sent from the sub ink reservoir is instantly absorbed by the ink absorption body, so that ink does not run over from the pen body. When the ink is desired to be supplied, the ink suction body sucks ink from the main ink reservoir, so that the ink from the main ink reservoir can be supplied surely to the pen body.
Preferably, the small hole can have a diameter of 0.3 to 3.0 mm. Thereby, a natural flow of ink from the main ink reservoir to the sub ink reservoir can be prevented by the surface tension of ink. The diameter of the small hole is preferably 1.0 to 2.0 mm.
The ink absorption body can be formed of any substance capable of absorbing ink. Preferably, the ink absorption body is formed of a porous substance. Thus, the ink absorption body can absorb a high capacity of ink, and therefore the quantity of ink that can be used in writing by one operation of the pen body can be increased.
The ink suction body can be formed with a plurality of capillary grooves on an outer peripheral surface thereof, and the capillary groove has a size capable of sucking ink from the main ink reservoir by a capillary force. Thus, by utilizing the capillary force, the ink suction body can suck ink surely from the main ink reservoir.
The present disclosure relates to subject matter contained in Japanese Patent Application No. 2001-359693, filed on Nov. 26, 2001, which are expressly incorporated herein by reference in its entirety.